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Is it new battery time ?

3K views 40 replies 15 participants last post by  aleks001 
#1 ·
Hi,

Just wanted to get an opinion. My car has been parked for two days, when I parked it I checked the battery voltage and it was 12.67 after standing for 2 days its is at 12.13. Is this drop too much for two days or is it normal.

Note: It is quite possible that this is the original car battery from 2006 lol
 
#2 ·
Have you received the "High Battery Discharge" warning? If not I wouldn't be concerned about it until such time as you begin to receive it. Once you do it's likely time to replace it Just went through this over the past couple of weeks. Replaced mine on Friday.
 
#7 ·
If you're at 12.13 volts after two days of sitting, you either have a battery that's on its last legs or a parasitic draw that needs to be corrected. That's a drop of 1/2 volt in 48 hours, which is too much. Most cars will not start if the battery is under 12V.

Unless you have been modifying the car's electrical system (which might result in a parasitic draw) my vote is to replace the battery. If you want, since the battery is $$, you might have a test run on the battery.
 
#12 ·
06 325 the battery 6 years old time for replacement

06 325 the battery 6 years old time for replacement if original.
You got as much as most people get out of it unless you keep it
hooked up to a battery tender at all times. If you did that from the beginning it might
go a couple more years .
 
#13 ·
Yeah, you're probably close to a dead battery. My light has been coming on if I leave the car in ACC for a few minutes. I measured the volts from under the hood: 14.71 running, 12.05 off, and 11.77 when the battery light came on.
 
#21 ·
Are you reading the voltage right after unlocking the car? For the first few minutes, the voltage drops because (I'm assuming) some systems are powering up? If I unlock my car and measure, its around 12.13. If I leave the hood open and come back in 15 mins, the voltage is in the high 12s.
 
#31 ·
FWIW: When my OEM battery went south (apparently because of my bad behaviour), never once did I get a LOW BAT signal. It just wouldn't fire up. Upon pushing the key into the slot on the dash and pressing the start button I got all sorts of clicking and flashing dash lights, but no definitive warnings.

The lesson being, you can slowly drive a battery to it's death, like I apparently did with limited mileage hops and repetetive door opening cycles without locking the car. Now, every time I get out of the car, I lock the door. I also now, routinely tender the battery after the car's weekly bath.
 
#32 ·
When you guys (and gals) shut your cars off, are you holding down the button long enough? When I bought my car, the previous owner told me to hold down the off button so it completely shuts off.

FYI, I had "increased battery discharge" warnings last night and this morning (was playing around with my dkan cable last night). I measured the voltage after half an hour from returning home from work and got 12.32. Seems my battery is still fighting to stay alive :)
 
#34 ·
My 2 cents for what it is worth; get a new battery. If anything, it will give you a peace of mind. I have the original battery in our '07 E90 and have used a tender on it every winter while the car sleeps. That being said, I intend on replacing it this spring just for prevention purposes. Much like the OP, I don't need to get stranded anywhere due to a dead battery.

A
 
#40 ·
Check after 18 minutes as this is when the car goes to sleep mode
 
#41 ·
Ok, so day 4, unlocked the car it read 11.98 immediately and started to creep up slowly lol. So I waited 20 minutes and it finally rested at 12.12

So I think the battery is still good, it's obviously not at it's best, but I think it's got plenty left. I will charge it up and continue using it.
 
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